1. Field of the Invention
Exemplary embodiments relate to an apparatus and method for identifying a transmission control protocol (TCP) packet loss to support a high-speed data communication service.
2. Description of the Related Art
For reliable end-to-end data transmission, transmission control protocol (TCP) is used in a transport layer of an open systems interconnection (OSI) 7 layer model.
In a network having a long transmission delay and a high transmission link loss rate, TCP may be deteriorated. Also, since TCP is designed for wired networks, TCP may fail to control a network congestion adaptively based on characteristics of networks in a wired and wireless mixed network environment.
For example, TCP may execute a congestion control when a packet loss occurs due to a link degradation of a wireless channel as well as when a packet loss occurs due to a network congestion, irrespective of a cause of the packet loss occurring. This unnecessary congestion control may lead to an unfavorable result, for example, a throughput reduced to half, cwnd=cwnd/2.
In this case, TCP may require a long period of time to recover a previously reached sending rate, which fails to maintain a high throughput in a wireless network having a high packet loss rate, resulting in a low network utilization.
To resolve this issue, a new TCP scheme, for example, TCP Westwood, TCP New Jersey, TCP Veno, and the like, have been proposed to improve the performance in a wireless network environment.
TCP Westwood may estimate an available bandwidth for each acknowledgement (ACK) packet received. On a packet loss, a slow start threshold (ssthresh) and a congestion window (cwin) may be set to be an estimated available bandwidth value.
When a packet loss is detected by three identicate ACKs, TCP Westwood may determine that the packet loss is caused by a link degradation of a wireless channel, and may calculate and set a number of packets to be transmitted, based on ssthresh and cwin as an estimated available bandwidth value.
When a timeout occurs, TCP Westwood may determine that the timeout is caused by network congestion, and may calculate and set a number of packets to be transmitted, based on cwnd=1 and ssthresh as an estimated available bandwidth value.
Accordingly, a need exists for a method of resolving an issue of reduced TCP throughput caused by unnecessary congestion control due to an incorrect determination as to packet loss and network congestion being present in a wired and wireless mixed network environment.